An only child growing up in Chicago, Bree Goldstein always wondered about life with siblings. When she hung out with friends who had a brother or sister, she was amazed by their relationships: "It was always cool to see someone who knew everything about your life, and was there for you no matter what, but in a way that’s different from a parent," she recalls. She longed to have that for herself.

By her sophomore year at Dickinson College, in 2002, she thought she saw her chance, setting her heart on getting into a sorority. She had a whole vision of what her sorority sisters would mean for her long-term future: friends for life, bridesmaids, mothers-in-arms.

But her plan ran into a hitch. That fall, all the sororities she rushed rejected her. "I was a little bit upset," she admits.

The following January, Goldstein wandered into Dickinson’s volunteer fair. She wandered over to a table manned by a local volunteer fireman. She introduced herself to the tall, mustachioed man, who looked at her skeptically. He explained that the local firehouse had had a few student volunteers who were men, but never any women. The mustachioed man alluded cautiously to the physical demands of the job. Nonetheless, he gave her a flyer.

The following Saturday, Goldstein walked to the firehouse. Finding the engine bay empty, she knocked on a nearby door, and entered what turned out to be the break room. Five men, ranging in age from their 20s to around 50, sat on old green couches. A fishing show flickered on a nearby TV.

"Are you lost?" one of the men asked Goldstein.

"I’m Bree," she said. "I want to be a firefighter."

In front of the fire engine (training): Chief Dave Weaver, Bree Goldstein, Brian Schaffner, Tony Tricarico*, Ron Bouch, Michael Rugh (Spring 2005, Carlisle, PA) *Tony was with FDNY. He came down to lead a R.I.T. training. R.I.T. stands for Rapid Inter-vention Team, which are the best of the best - they’re called in when the fire fighters are in trou-ble. He lead a R.I.T. in NYC.

The men examined her with raised eyebrows. Goldstein was 19 years old, 5’2", and overweight.

But the men were nothing if not polite. They indulged what they were sure was the fleeting idea of one those preppy kids from the college. They showed her the engine bay. They showed her how the radio worked. They showed her the gear, explaining that it was in short supply. Goldstein asked question after question. Two hours passed.

The men sent Goldstein off sure they’d never see her again. But the first thing Goldstein did when she got back to her dorm was call her mother. "Guess what I did today?" she gushed.

The men’s names were Ricky, Bo, Danny, Steve, and Merlin. As it turned out, Goldstein wasn’t destined to have sisters, but brothers.

Goldstein went in the very next day. She asked question after question. She stayed for three hours, listening to calls as they came in, figuring out how the radio worked. Alarms kept coming over the radio and Goldstein kept leaping to her feet, sure the men were about to mobilize. It took a while for her to learn that the alarms, whose tones varied, were coded—and only one code in particular was a call to Union Fire Company Number 41.

Goldstein signed up as a probationary firefighter. She got a textbook, went out to training grounds, learned how to handle hazardous materials, how to rapidly get in and out the gear. She trained by running up and down stairs. Eager to please the other firefighters, she leapt on any job, no matter how small. No one liked to file reports, so she took those on. She asked so many questions that one of the men instituted a 10-per-day rule.

Goldstein’s first real-life test came about two months into her training. A call came in about a car wreck on the nearby highway. Goldstein piled into the fire truck with the men, and they went zooming off. On the way, a semi-truck cut them off, nearly hitting them. "We weren’t even at the scene, and I was already terrified," remembers Goldstein.

They arrived at the edge of the highway. Cars zoomed by at full speed. An ambulance was on the way to pick up the injured driver, but Goldstein and the others were tasked with cleaning up the debris. She focused on following protocols, trying not to be terrified by the cars careening past, just feet from her. She managed to do her job, and the fire company headed back to the firehouse.

Not long after, one of the firehouse’s leaders, Richard Middlekauf, took her aside. "You’re alright," he told her. "You’re gonna be just fine."

She remembers around this time going out to lunch at a Cracker Barrel with the guys after another call. They ordered food, set the radio in the middle of the table, and started shooting the shit. Goldstein tossed a joke in, and the guys all laughed.

Goldstein sat back in her chair and took it all in. She trusted these people more than she’d ever trusted anyone. She was one of them. "Oh my God," she thought. "This is amazing. I’ve never felt this."

Goldstein served as a volunteer firefighter through her sophomore, junior, and senior years at Dickinson. She lived between two worlds. One moment she’d be in a seminar, the next she’d be venturing into a flame-engulfed structure. Her junior year of college, Goldstein moved into the firehouse, spending four to five nights a week there. She spent as much as 50 hours a week on duty.

She faced fires, bomb threats, car accidents. When she learned that one of her colleagues spent his summers rappelling from helicopters to fighting forest fires in Oregon, she signed up for two summers to serve on an engine crew there. "The only kind of call I didn’t experience was a cat stuck in a tree," she says.

She says she learned all kinds of skills as a female firefighter that have served her later in life, as an entrepreneur. (She founded UpDog, a video reviewing app.) Grit, determination, an appetite for risk. A willingness to push against established norms. She knows that if she hadn’t been a firefighter, she wouldn’t be quite the same person.

"It’s absolutely given me the determination to say, ‘I’m gonna do this,’ and put everything I have towards it," she says. "It taught me to be fearless. There’s nothing scarier than a fire, right?" Any time her heart flutters a moment before pitching a VC, she can remember that she used to dash into burning buildings.

Back in college, as Goldstein's career at the Carlisle firehouse progressed, the inevitable finally came: graduation.

A few of the firefighters showed up in an old fire engine one of them had bought. Afterwards, she went back to the firehouse to hang out. "I’ll be back!" she kept telling them. "Sure you will..." they said. But part of her was genuinely wondering whether she might move back to the area soon, try to build a life there.

Hanging from a window (training): Bree Goldstein, and Michael Rugh

Her dad piled her into the car, and they drove back to Chicago. She thought of her firehouse buddies often, but this was back when Facebook was exclusively for college students, so Goldstein wasn’t able to friend the men to maintain that kind of casual digital contact.

She did go back briefly just two weeks later to visit. It already felt very different. There were new recruits, half of whom she’d never met. Her gear had been given to someone else. "It just didn’t have the same feeling," she says.

"That’s when it occurred to me it was time to move on," she said.

The last time she visited was at her five-year college reunion. When she walked over to the engine bay, she didn’t see a single person she knew. The door to the break room was closed. She knew the rules by now: The break room was for firefighters, only—and she wasn’t one anymore.

"I wanted to keep my memories, the way I knew it," she says. She walked away.

She got married in 2014 to "the best life partner you could ask for," she says. Richard Middlekauf, the fireman who had given her early encouragement (and remained close), spoke at her wedding. Goldstein now has a 3-month-old son, and says she hopes to give him a sibling someday. She’s very happy.

But she’s never recaptured that fraternal feeling of the firehouse, she says a bit wistfully. "That’s always kind of been the missing piece."

Never miss a story.

Get the best stories from our Most Creative People series delivered to your inbox weekly.